[dwarfdump] Verify that CUs have a unit DIE.

This patch adds a check to the DWARF verifier to detect CUs without a
unit DIE.

Differential revision: https://reviews.llvm.org/D38363

llvm-svn: 314426

2 files changed, 29 insertions, 3 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index 096d5ff8c33..eadb982ba72 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -179,9 +179,14 @@ bool DWARFVerifier::verifyUnitContents(DWARFUnit Unit) {
     }
   }
 
-  DieRangeInfo RI;
-  DWARFDie Die = Unit.getUnitDIE(/* ExtractUnitDIEOnly = */ false);
-  NumUnitErrors += verifyDieRanges(Die, RI);
+  if (DWARFDie Die = Unit.getUnitDIE(/* ExtractUnitDIEOnly = */ false)) {
+    DieRangeInfo RI;
+    NumUnitErrors += verifyDieRanges(Die, RI);
+  } else {
+    OS << "error: Compilation unit without unit DIE.\n";
+    NumUnitErrors++;
+  }
+
   return NumUnitErrors == 0;
 }
 
diff --git a/llvm/test/tools/llvm-dwarfdump/X86/empty-CU.s b/llvm/test/tools/llvm-dwarfdump/X86/empty-CU.s
new file mode 100644
index 00000000000..14ff75836f4
--- /dev/null
+++ b/llvm/test/tools/llvm-dwarfdump/X86/empty-CU.s
@@ -0,0 +1,21 @@
+# RUN: llvm-mc %s -filetype obj -triple x86_64-apple-darwin -o - \
+# RUN: | not llvm-dwarfdump --verify --debug-info - \
+# RUN: | FileCheck %s
+# CHECK: error: Compilation unit without unit DIE.
+
+        .section        __DWARF,__debug_info,regular,debug
+.long 8  # CU length
+.short 3 # Version
+.long 0  # Abbrev offset
+.byte 4  # AddrSize
+.byte 1  # Abbrev 1
+.long 7  # Unit lengthh...
+.short 3
+.long 0
+.byte 4
+        .section        __DWARF,__debug_abbrev,regular,debug
+.byte 1    # Abbrev code
+.byte 0x11 # TAG_compile_unit
+.byte 0    # no children
+.byte 0    # no attributes
+.byte 0